Lancer

ABSTRACT

A lancer device that enables a user to draw blood from a patient and discard the used lancet without touching it. The device also has an adjustable tip for selecting the depth of stylet penetration into the patient and a triggering mechanism that utilizes a yoke latch and a leaf spring to discharge the lancet. The lancer also has a dampening feature to reduce vibrations when the lancet is moving.

This application is a divisional of application Ser. No. 10/400,739,filed Mar. 27, 2003, which is a continuation of application Ser. No.09/366,149, filed Aug. 3, 1999, now U.S. Pat. No. 6,558,402, both ofwhich are incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lancer for withdrawing a sample ofblood from a patient via a lancet. More particularly, the invention isdrawn to a lancer having a latch triggering mechanism for actuating thedevice. The lancer optionally has an adjustable tip for setting thedepth of penetration of the lancet into the patient's skin by moving alancet stop back and forth. The lancer may further include an ejectionmechanism for automatically causing the release of the lancet from thelancer without the need to handle the lancet. Moreover, the lancer mayinclude a dampening mechanism, such as a wisp, for reducing vibrationsin the lancet, thus increasing patient comfort. The lancet may furtherinclude a centering mechanism to decrease undesired motions of thelancet perpendicular to the axial direction, when the lancet is fired.

2. Brief Description of the Art

Ballistic-type lancers are commonly used devices in the medical fieldfor making a small puncture in a patient's skin to obtain a bloodsample. One such lancer comprises a hollow lancer body and a lancetcontaining a sharpened needle, also known as a stylet. The lancet ismounted by the user onto a plunger within the lancer body. The plungeris capable of moving axially (back and forth) within the lancer body.The plunger is surrounded by a coil spring, which becomes compressedwhen the plunger is pulled back or “armed” by the user. The plunger isheld in place by a trigger with the compressed spring exerting a forceagainst the plunger. The lancer is now said to be in an armed state. Thearmed lancer is grasped by the user and its bottom is pressed againstthe patient's skin. When the plunger is released by the user byactuating the trigger, the spring decompresses, driving the plunger, andthe attached lancet, toward the bottom of the lancer. As the propelledlancet hits a stop at the bottom of the lancer, its projecting stylet ispushed through a hole in the stop, which in turn swiftly pierces thepatient's skin so that a drop of blood can be removed therefrom. Thatdrop of blood may then be used for testing, such as blood glucosetesting for diabetics. This lancer, however, does not completely meetthe needs of patients and other users, such as medical personnel whoemploy the lancers to obtain samples from patients, for reasonsdescribed below.

To hold the plunger in the armed state, the conventional lancer,described above, uses a pawl-like trigger integrally attached to thebottom end of the plunger. When the plunger is cocked, the tip of thepawl-like trigger is received into an opening in the lancer body,thereby holding the spring-loaded plunger in place. A small button ispositioned over the lancer body opening to allow the user to actuate thetrigger, i.e., push the pawl tip out of the receiving hole and back intothe lancer body. This pawl-like or detent-based trigger, however, can beactuated with relatively little force, which may result in aninadvertent firing of the lancet and the accidental piercing of thepatient's or user's skin. Therefore, an improved triggering mechanism isdesired that reduces the likelihood of accidental firing by actuatingonly when sufficient and intended pressure is applied thereto.

Also, because the pawl-like trigger is integral to the plunger, itplaces a bias force on the plunger. That bias force, however, is not inthe same direction of the spring force on the plunger, and may adverselyaffect the operation of the plunger by causing it to deviate from itsaxial path of motion. This in turn can reduce patient comfort uponpenetration of the stylet. Consequently, it is also desired that theimproved triggering mechanism minimize introduction the of non-axialmotion to the plunger so that it can have a more linear path of motion,thus increasing patient comfort.

The penetration depth of the stylet into the patient's skin is anotherimportant consideration in patient comfort, as well as being a majorfactor in determining the amount of blood that will be obtained from thepatient (stylet gauge being the other major factor). Generally, as thestylet penetration depth increases, the amount of blood increases, aswell as the patient discomfort. However, the required depth ofpenetration will differ from patient to patient, because skin thicknessvaries depending on the patient's age, gender, the extent to which ithas been previously lanced, and other factors. If the penetration depthis set by the lancer design to be too shallow for the specific patient,the stylet may not adequately pierce the patient's skin, and repeatedlancing attempts or smaller gauge (larger diameter) stylets may berequired to extract the required amount of blood, which in turn wastestime and/or lancets, and in any event increases patient discomfort. Onthe other hand, if the lancer is designed to cause the stylet topenetrate too deeply for a specific patient, unnecessary discomfort willbe incurred by that patient, as well as a longer recovery time.

A certain conventional lancer has been designed to have an adjustablestylet firing depth, wherein the distance that the plunger moves isprecisely controlled to achieve the desired penetration depth of thestylet. However, to achieve this precise plunger control, complicateddrive mechanisms involving many low tolerance and expensive componentsare required, as well as time-consuming and labor-intensive assembly.

Other conventional lancers allow for imprecise plunger movement, butinstead accommodate cap (or tip) assemblies to permit the patient orother user to set for himself or herself a desired stylet penetrationdepth. The bottom of the cap assembly stops the movement of the lancet,and the stylet passes through a hole in the bottom of the cap to piercethe skin. For example, one type of lancer is designed to receiveinterchangeable caps. Each cap has, at its bottom, an annular stopportion, to stop the lancet. The lancet stop surrounds the hole thatlets the stylet pass through. The bottom of the cap assemblies are eachmade to have a different thickness. Thicker bottoms provide a shallowerstylet penetration depth, and thinner bottoms provide a deeper styletpenetration depth. The user selects the desired depth of penetration byplacing one of the set of interchangeable caps onto the lancer. Thisadjustment technique, however, requires the manufacture, stocking andpurchase of many various cap assemblies of differing thickness.

Another type of depth penetration adjusting assembly works by placingthe lancet stop portion within the assembly itself. The bottom (distal)portion of the assembly has a hole that corresponds to the hole withinthe lancet stop, and the stylet passes through both the lancet andbottom holes. In this type of adjustable cap, the bottom of the cap iscaused to move back and forth to provide respectively a smaller orlarger space between the lancet stop and the bottom of the cap, which inturn respectively increases and decreases the stylet penetration depth.

One such depth penetration adjustment assembly includes three elements.The first is a cap element having its near end coupled to the lancer. Atthe distal end of the cap element is the lancet stop and an openingthrough which the stylet passes. The assembly secondly includes a coverelement forming its bottom. The cover element also has an openingthrough which the stylet passes that corresponds to the opening in thecap element. The assembly has a third adjusting element disposedbetween, and engaging, the cap and cover elements. The adjusting elementhas a recessed portion on its outside to engage the cover element, whichpermits the adjusting element to rotate with the cover element whenengaged. The adjusting element/cover element subassembly are engaged tothe cap element via a threaded fitting, which allows the adjustingelement/cover element subassembly to turn like a screw with respect tothe cap element, which translates into axial movement of the bottom ofthe cover element with respect to the lancet stop of the cap element.This causes a variation of the stylet penetration depth. However, thisdevice requires the manufacture and assembly of three discrete elements.Moreover, because the bottom cover element moves to achieve a variationin depth, the overall length of the lancer will vary depending on theadjustment setting, inhibiting easy storage and use of the lancer. Also,the depth setting can change since the tip may be rotated while beingassembled on the device.

Another conventional depth penetration adjustable cap assembly also usesthree elements: an inner sleeve having the lancet stop, an intermediatering having a first helical incline camming surface, and an outersleeve, having the bottom opening and a second helical incline cammingsurface. This assembly is likewise coupled to the lancer. The cammingsurfaces of the combined assembly capture a cam on the inner sleeve.When the outer sleeve is rotated, the cam forces the outer sleeve tomove away from the lancer, thus increasing the distance between thelancet stop and the bottom of the outer sleeve, which in turn decreasesthe depth penetration. This assembly, however, suffers from the sameproblems as the previously described one.

Although all of the above-described adjustable depth penetrationassemblies regulate the amount of skin penetration, and to a certainextent allow for easy adjustment, it is desired to have one thatminimizes resetting errors when removing and replacing the cap.

In another aspect of conventional lancer operation, after the lancet hasbeen used to draw blood from a patient it becomes contaminated withblood and, thus, poses a potential health hazard to anyone else whomight be stuck by its stylet. Conventional lancers with ejectioncapabilities typically utilize a control member that is held by anoperator. Unfortunately, if the operator removes a finger from thecontrol member prior to complete separation, an accidental lancetejection can result. In an attempt to prevent this, one conventionaltype of ejection mechanism utilizes a retention recess that retains thecontrol member to permit ejection. This solution is less than optimalsince there is still a possibility of accidental ejection. Other knownejection mechanisms tend to be cumbersome and require complicatedmanipulations, which are difficult for blind or disabled diabetics toaccomplish, and increase the likelihood of accidental needle stickinjury. In order to overcome the problems associated with the knownlancet ejection mechanisms, it is desirable for the lancer to be capableof easily and automatically ejecting the contaminated lancet with thepatient or other user using motions already known or familiar to theuser.

In another aspect of conventional lancers, the spring-loadedplunger/lancet assembly may produce vibrations upon it being fired. Inparticular, the release of the compressed spring exerts a force on aplunger/lancet assembly to accelerate the same. The lancer's systemdynamics, due primarily to the main spring that accelerates the plunger,are such that the plunger may vibrate in the axial direction after thelancet has rebounded from its stopping component. These vibrations maythus reduce the optimum propulsion of the lancet and reduce the comfortof the patient, because even small vibrations can be sensed by thepatient upon lancing of the skin. It thus would be desirable to providea lancer having a mechanism for dampening these vibrations andfrictional dampening of axial movement, and thereby increase the comfortof the patient.

It would also be desirable to provide a lancer that has a mechanism toreduce radial movements of the plunger and thereby increase patientcomfort by reducing radial forces introduced by the lancet stylet whenit is penetrating the patient's tissue.

SUMMARY OF THE INVENTION

The present invention is drawn to an improved lancer having featuresthat improve the safety of the device and increase the comfort of thepatient. The lancer can include a triggering mechanism that will beactuated when a user deliberately applies the required force to fire thelancet. A swift release and retraction of the lancet provides improvedoperation of the lancer. The lancer also optionally has an adjustabletip portion that permits a user to select a desired depth of styletpenetration from a number of depth-penetration choices. This featurefacilitates an adequate, reproducible lancing for the user or patient.The lancer may also optionally include an ejection mechanism thatreleases a used lancet without the user or patient touching the usedlancet. The lancer optionally includes a vibration-reducing anddampening mechanism to increase patient comfort. These features providean improvement over conventional lancer devices.

Accordingly, an embodiment is directed to an apparatus for propelling alancet. This apparatus includes a body assembly that has a proximalportion, a distal portion, and an orifice disposed at the distal portionof the body. A guiding member is disposed in the body assembly andguides the lancet. A latch is disposed in the body assembly and engagesthe guiding member. The latch has at least one notch for engaging theguide member when the guide member is retracted. Upon actuation, thelatch causes the guide member to disengage from the notch and propel thelancet toward the orifice at the distal portion of the body assembly.

The actuation is suitably facilitated by tangs moving past an inclinedsurface of the notch(es) of the latch.

Another embodiment is directed to an adjustment assembly, attachable toa lancer having an outer member and an inner member. The outer memberhas a distal portion, and a proximal portion, the distal portion havingan exterior surface and an interior surface and an orifice from which aportion of the lancet emerges. The inner member has exterior andinterior surfaces and is positioned relative to the outer member suchthat when the outer member is rotated, the inner member moves relativeto the body assembly. This motion of the inner member is axially(forward and backward) and adjusts the distance between the inner memberexterior surface and outer member interior surface.

Yet another embodiment is directed to an apparatus for propelling alancet. This apparatus includes a body assembly, which has a proximalportion, a distal portion, and an orifice. A guide member is disposed inthe body assembly, for guiding the lancet. An ejection mechanism isdisposed in the body assembly, for preventing retraction of a lancet,when the guide member is rearwardly moved beyond a latching position,thereby detaching the lancet from the guide member following rearwardpositioning of the guide member. This rearward positioning of the guidemember is facilitated by detachment of the nose portion.

Yet still another embodiment is directed to an apparatus for actuating alancet. This apparatus includes means for guiding the lancet, disposedin the apparatus. It also includes means for actuating the guidingmeans, the actuating means having at least one notch. The actuatingmeans engages the guiding means when the guiding means is retracted, andreleases the guiding means from the actuating means when actuated.

Yet still another embodiment is directed to an apparatus for propellinga lancet. A body assembly has a proximal portion, a distal portion, andan orifice disposed at the distal portion. A guide member is disposed inthe body section, for guiding the lancet. A latch, for actuating theguide member, is disposed in the body assembly. A means for dampeningvibration is disposed on the guide member for reducing vibration of theguide member.

Yet still another embodiment of the instant invention is directed to alancer having a yoke latch wherein actuation of the yoke latch causes itto move substantially perpendicular to the axis of the device.

Yet still another embodiment is directed to a method for ejecting alancet, from a device having proximal and distal portions, and thedevice having a body assembly, a guide member and a cap portion,comprising the steps of:

loading the lancet onto a guide member;

retracting the guide member proximally to a first position;

actuating the guide member to propel the lancet;

retracting the guide member proximally to a second position, the secondposition being beyond the first position in the proximal direction;

exerting a force, in the distal direction, on the lancet sufficient todetach the lancet from the guide member.

Additionally, a cap portion can be attached to the body assembly afterthe lancet is loaded and detached prior to retracting the guide member.

Yet still another embodiment is directed to a lancer device having aretention mechanism for preventing the device from inadvertentlybecoming armed when a user is attempting to load or unload a lancet.This device includes a guide member, disposed in a body assembly, forguiding the propelled lancet. A latch is disposed in the housingassembly and has at least one notch for engaging the guide member whenthe guide member is retracted. Actuation of the latch causes the guidemember to disengage from the notch and propel the lancet toward theorifice at the distal portion of the body assembly. A retentionmechanism, disposed in parallel with the longitudinal axis of theapparatus abuts a portion of the lancet and thereby prevents axialmotion of the lancet. Thus, after firing, a portion of the latchprevents retraction of the guide member in the proximal direction.

Yet still another embodiment is directed to an apparatus for propellinga lancet. This apparatus has a body assembly, having a proximal portion,a distal portion, and an orifice disposed at the distal portion. A guidemember is disposed in the body assembly, for guiding the propelledlancet. The apparatus also has means for reducing radial instability ofthe guide member while the guide member is propelling the lancet.

Yet still another embodiment is directed to a lancet having a basemember and a stylet with an outer diameter of 31 gauge or smaller (i.e.,higher gauge, such as 32, 33 etc.).

Yet still another embodiment is directed to an adjustment apparatusattachable to a lancer body assembly. This apparatus includes an outermember, having a distal surface, an orifice through the distal surface,and a plurality of slots disposed on an interior surface of the outermember, each slot having a distinct axial depth. An inner member has adistal surface, an orifice through the distal surface, and a protrusion,or a plurality of protrusions, extending from an exterior surface of theinner member. The protrusion(s) is insertable into one of the pluralityof slots on the interior surface of the outer member so as to establisha distance between the distal surface of the inner member and the distalsurface of the outer member. A biasing means is disposed around theinner member and is used to bias the outer member toward the innermember.

Yet still another embodiment is directed to an adjustment apparatushaving an interior member with a plurality of slots, and an interiormember with at least one protrusion, for insertion into a selected slot.

Yet still another embodiment is directed to an apparatus for propellinga lancet having a body assembly, with a proximal portion, a distalportion, and an orifice disposed at the distal portion. A guide memberis disposed in the body assembly, for guiding the propelled lancet. Alatch is disposed in the housing assembly, for engaging the guide memberwhen the guide member is retracted and disengaging the guide member whena sufficient force is applied to the latch to cause the latch to deform.The force permits the guide member to pass through the latch.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a perspective view of a lancer device.

FIG. 2 shows an exploded view of component parts of the lancer device.

FIGS. 3A-3F show exploded views of a first embodiment of an adjustmentmechanism.

FIGS. 4A-4H show views of the first embodiment of the adjustmentmechanism.

FIGS. 5A and 5B show a cross-sectional view of the first embodiment ofthe adjustment mechanism.

FIG. 6 shows a cross-sectional view of a second embodiment of theadjustment mechanism.

FIGS. 7 and 8 show an exploded and partial cut-away view of a thirdembodiment of the adjustment mechanism.

FIG. 9A shows a cross-sectional view of the third embodiment of theadjustment mechanism.

FIG. 9B shows a cut-away view of the third embodiment of the adjustmentmechanism.

FIGS. 10A and 10B show a fourth embodiment of the adjustment mechanism.

FIGS. 11A, 11B and 11C show a fifth embodiment of the adjustmentmechanism.

FIGS. 12A and 12B show a sixth embodiment of the adjustment mechanism.

FIG. 13 shows an exploded view of a seventh embodiment of the adjustmentmechanism.

FIG. 14 shows an eighth embodiment of the adjustment mechanism.

FIGS. 15A and 15B show an isometric view of a support member as itrelates to the triggering mechanism of the lancer device.

FIGS. 16A and 16B show a perspective view of a yoke latch of the lancerdevice.

FIG. 17 shows a perspective view of a button of the lancer device.

FIG. 18 shows a perspective view of a retaining member used with thelancer device.

FIG. 19 shows a cut-away view of the lancer device in a restingposition.

FIG. 20 shows a cut-away view of the lancer device in an armed position.

FIG. 21 shows a cut-away view of the lancer device in an armed positionwith an end knob extended.

FIG. 22 shows an exploded view of the lancer device with an ejectionmechanism.

FIG. 23 shows a cut-away view of the lancer device having an ejectionmechanism.

FIG. 24 shows a cut-away view of the lancer device having an ejectionmechanism, in the armed position.

FIG. 25 shows a cross-sectional view of the lancer with the ejectionmechanism.

FIG. 26 shows a perspective view of a sleeve member.

FIG. 27 shows a perspective view of a plunger having avibration-dampening mechanism.

FIG. 28 shows vibration-dampening members.

FIG. 29 shows a mechanism for reducing radial movement of the lancet.

FIG. 30 shows an exploded view of an oblong lancer device.

FIGS. 31A and 31B show the oblong lancer device.

FIG. 32 shows an cut-away view of oblong lancer device.

FIG. 33 shows a partial cut-away view of the adjustment portion of theoblong lancer device.

FIG. 34 shows the plunger and latch of the oblong lancer device.

FIGS. 35A-35C and 36 show a perspective view of a stylet.

FIG. 37 shows a perspective view of the stylet with a shield.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Lancer devices are typically used to obtain a blood sample from apatient by piercing the skin so that a small amount of blood can bewithdrawn. For example, ballistic-type lancer devices are typicallydesigned to be used in conjunction with narrow gauge lancets to obtain adrop of capillary blood for use in a low-volume blood glucose monitor.One such glucose monitor requires approximately 2.5 micro-liters ofcapillary blood.

FIG. 1. shows a perspective view of the lancer device 10. The device 10has a body assembly (also referred to as body section herein) 136 havingdistal portion 228 and proximal portion 230. Tip cap (also referred toas nose cap or nose portion) 104 is connected to body assembly 136 atdistal portion 228. Nose portion 104 has a surface 168 at its distal endfor pressing against a patient's flesh. Nose orifice 184 is formed innose portion 104 for permitting the lancet stylet (not shown in FIG. 1)to emerge from the lancet device 10. Indication marks (not shown inFIG. 1) of the position of stylet stop (not shown in FIG. 1) are visiblethrough nose portion notch or window 112. The notch 112 suitably has atranslucent lens 115 covering the notch 112. The lens 115 magnifies thesetting of the device, which is visible through notch 112. The settingis adjusted by the user and indication marks are marked on a portion ofadjustment collar 106 so as to provide an indication to the user of thedepth penetration of the stylet. Adjustment collar 106 is rotatablearound nose portion 104 to set the desired depth of penetration. Theuser can change the setting by rotating the adjustment collar 106 to adesired setting. This is accomplished by grasping bumps or continuousknurl, shown as element 114, which are suitably raised grooves on theexterior surface of adjustment collar 106. Alternatively, element 114could include Braille markings to facilitate a desired setting byseeing-impaired users.

Release member 138, which is suitably a button, is part of thetriggering mechanism (complete triggering mechanism is not shown inFIG. 1) of lancet device 10. The triggering mechanism is designed sothat a substantial portion of release member 138 extends above the outersurface of body assembly 136 when the release member 138 is notdepressed. Knob cap 122, also referred to as end knob herein, isdisposed at the proximal portion 230 of body assembly 136. The end knob122 is used to arm the device 10.

FIG. 2 shows an exploded view of the lancer device 10. Body assembly 136is suitably a hollow, substantially cylindrical member with a bodyorifice 214 and button orifice 216 located at the distal end 228 of bodyassembly 136. Body orifice 214 provides a passageway for plunger 146 topush a lancet (not shown in FIG. 2) in the direction of nose portion104. Body orifice 214 also provides a mounting location for tip threadend 116. Button orifice 216 provides a location to mount release member(also called a button herein) 138 to body assembly 136. Button 138 isused to actuate triggering mechanism 172. The body assembly 136 housesvarious mechanisms of the lancer device 10. These mechanisms include: anadjustment mechanism 108, for selecting the depth of stylet penetration;an arming mechanism 166, for cocking or loading the lancer prior tofiring; a trigger mechanism 172, for actuating the lancet; a supportmechanism 175, for guiding the lancet so that a stylet (not shown inFIG. 2) emerges from the lancet device 10; and an ejection mechanism(not shown in FIG. 2), for ejecting a used lancet into an appropriaterefuse container.

The components of each mechanism will now be described; however, thecomponents of each mechanism are described as an exemplary embodimentand each mechanism does not necessarily require all of the componentsdiscussed in relation to that mechanism. Indeed, as will be apparent toone skilled in the art, the mechanisms are capable of operation withless than all of the components discussed, as well as with substitutionsof the components.

The adjustment mechanism 108 enables a user to select a desired depth ofstylet penetration into a patient's skin. When using lancer device 10,it is desirable to have a puncture depth sufficient to obtain thenecessary blood sample. Typically the puncture depth in the patientshould be in the range of approximately between 0.015 inch and 0.140inch, and preferably between 0.024 inch and 0.105 inch. To accommodatedifferent skin thicknesses and conditions the lancet device 10 has anadjustment mechanism 108. This adjustment mechanism 108 suitablyincludes a nose portion 104, a lancet stop 102, an adjustment collar 106and a tip thread end 116.

The nose portion 104 is suitably ogival shaped with a diameter suitableto receive lancet stop 102, in a substantially mating relationship, in acavity formed in the proximal end of the nose portion 104. The noseportion 104 has distal surface 168, for interfacing with the patient'sskin, and nose orifice 184, which provides an opening for a stylet toemerge. Notch 112 is formed in nose portion 104 for revealing markings113 on adjustment collar 106.

Lancet stop 102 is suitably an ogival shaped member with dimensions thatpermit insertion into nose portion 104. Lancet stop 102 has two U-shapeddepressions or notches (only one notch 266 is shown in FIG. 2) and anorifice 246. Lancet stop 102 is disposed within nose portion 104 suchthat the lancet, upon actuation, will abut the lancet stop 102, therebyresulting in a predetermined extension of the stylet beyond distalsurface 168 of nose portion 104. Lancet stop 102 has one or moreprotrusions shown as 244(a) and 244(b) (although only two protrusionsare shown, there could be more or less than two, and virtually anynumber that comports with the design would be acceptable) that extendradially outward and interact with surface 107, which is for example acaroming surface or screw threads, in adjustment collar 106, and theprotrusions 244(a) and 244(b) are constrained from radial rotationwithin aperture 165, which is also typically a slot, of tip threadmember 116. (Although only a single aperture is shown, there could beany number that comports with the design of the device 10.) This movesthe lancet stop 102 axially (i.e., back and forth) and thereby positionslancet stop 102 in nose portion 104.

The lancet stop 102 is used in conjunction with the nose tip 104 toadjust the penetration depth of a stylet. Lancet stop 102 has a distalsurface 222. The position of this distal surface 222 in relation to theinterior surface of nose portion 104 determines the distance a styletemerges from nose orifice 184. Lancet stop 102 is moved via a radialrotation of adjustment collar 106. The lancet stop 102 suitably has sixdepth settings from which the user may choose, typically numbered “1” to“6” that correspond to a particular stylet penetration. (The number ofdepth settings is a design choice and is not critical to theunderstanding of the invention.) The further lancet distal surface 222is from the nose orifice 184, the less a stylet will emerge from orifice184, and the less penetration into the patient's skin.

Adjustment collar 106 has an inner threaded surface 107, such as screwthreads or a camming surface, that permits rotation of the adjustmentcollar 106 about nose portion 104. The lancet stop 102 is moved viacollar 106 since lancet stop protrusions 244(a) and 244(b) engage aportion of collar 106 within the confines of surface 107. The lancetstop 102 is prevented from rotating with the collar 106 due to the fixedrelationship of protrusions 244(a) and 244(b) with aperture 165 of tipthread end member 116. Radial rotation of the collar 106 rotatesthreaded surface 107 and thereby cams a portion of the lancet stop 102.The lancet stop 102 is trapped from axial rotation due to protrusions244(a) and 244(b) being movably interlocked or slidably engaged in acorresponding aperture 165 in tip thread member 116. Radially locateddetenting features (shown in FIG. 4C) between the nose portion 104, orthe thread end member 116, and collar 106 keep the adjustment indiscrete intervals.

Adjustment collar 106 has markings 113 on a distal portion indicatingthe position of lancer stop 102 within nose portion 104. Thus, the useror patient can set the adjustment mechanism to a particular penetrationdepth prior to each use, if they desire.

Adjustment collar 106 has grooves, bumps, or other markings 114 forfacilitating a user or patient setting lancet stop 102 to a selecteddepth within nose portion 104. A continuous knurl surface suitably hasmarkings within the knurl.

Tip thread member 116 provides a coupling between adjustment collar 106and body assembly 136, via an optional sleeve member 186. The noseportion 104, having lancet stop 102 disposed therein, is attached to tipthread member 116, via optional sleeve 186, which is connected to bodyassembly 136. Typically, tip thread member 116 mounts in body orifice214 or abuts it.

Alternatively, the tip thread member 116 could mount to sleeve 186, orcollar 106 could mount to sleeve 186. Also, the tip thread member 116could be fabricated to be an integral part of nose portion 104.

Alternatively, the tip thread member 116 could be integral with bodyassembly 136.

Various embodiments of the adjustment mechanism will be discussed inrelation to FIGS. 3-14.

Turning first to FIG. 3A, which shows an exploded perspective view ofthe adjustment mechanism 108, nose portion (shown in FIG. 2 as element104) and tip thread member (shown in FIG. 2 as element 116) are a singlenose piece shown as element 1104. Nose piece 1104 has notch 112,aperture 165, and an elongated portion 256. Notch 112 only exposes anindication of the current penetration depth. However, the other settingsare obvious to a user because of the indicia, such as grooves, bumps orcontinuous knurl 114, which give the settings an intuitive feel.Elongated portion 256 has notches or grooves 266(a) and 266(b) forinterfacing with protrusions 466(a) and 466(b) of coupling 258.

Slot, also called an aperture, 165 interfaces with protrusion 244(a)thereby preventing substantial radial motion of the protrusion 244(a).(There could be additional slots to interface with protrusion 244(b);but a single slot/protrusion interface will adequately control lancetstop 102.) This interface between slot 165 and protrusion 244(a) permitslancet stop 102 to move primarily only in an axial direction when collar106 is rotated. The protrusion 244(a) interface with slot 165 preventradial rotation of lancet stop 102. The protrusion 244(a) is positionedso that it can move axially within aperture 165, causing lancet stop 102to move back and forth as collar 106 is rotated. Adjustment collar 106,with indicators 114, is mounted on the outside of elongated portion 256.Coupling 258 is used to retain adjustment collar 106 to single nosepiece 1104. Camming surfaces on nose piece 1104 provide a connectionmechanism to body assembly (not shown in FIG. 3A).

A pin protrusion 468 on nose piece 1104 interfaces with indentations, orcamming surfaces, (shown as detenting element 470 in FIG. 3B) on theinner diameter of collar 106 to adjust the relationship between collar106 and nose piece 1104 and prevent nose piece 1104 from axial motion,thus, collar 106 can only rotate relative to nose piece 1104. Thisprevents the overall length of the adjustment mechanism 108 fromchanging.

FIGS. 3B and 3C show cross-sectional and exploded views of adjustabletip mechanism 108. As seen in FIGS. 3B and 3C, the adjustment mechanismsetting does not alter the overall length of the device since the lancetstop 102 is moved axially within nose piece 1104, using threads orcamming surface 107. Thus, the nose piece 1104 does not extend orretract when the penetration depth is changed. Also, the depth ofpenetration does not inadvertently change when the lancer is in use orwhen the tip is detached and reattached. The collar 106, section 256,knurl 114, coupling 258 and protrusions 244(a) and 244(b) have beendiscussed in relation to FIG. 3A.

FIGS. 3D-3F show an embodiment of adjustment mechanism 108 in which thenose portion 104 with notch 112 interfaces with collar 106, tip threadmember 116 and lancet stop 102. The collar 106 has detenting surfaces470 to interact with a pin protrusion 468. (There are typically anysuitable number of detenting slots; but they are collectively shown aselement 470.) Protrusion 244(a) is positioned in slot 165, which permitssubstantially only axial motion and prevents virtually all rotation oflancet stop 102. Tip thread member 116 has camming surfaces 472 forinterfacing with either the body assembly or sleeve. (Neither the bodyassembly or sleeve is shown in FIGS. 3D-3F.) FIGS. 3D-3F are similar tothe embodiment shown in FIGS. 3A-3D except that the nose portion 104 isa distinct element from tip thread member 116. Both embodiments enableaxial (back and forth) motion of lancet stop 102, while preventingradial movement of lancet stop 102.

FIGS. 4A and 4B show perspective views of single nose piece 1104 andadjustment collar 106. (FIGS. 4A-4D are directed to a single nose pieceembodiment similar to the embodiment described in FIGS. 3A-3C above.) Asshown in FIG. 4A nose piece 1104 interfaces with adjustment collar 106such that notch 112 exposes a portion of collar 106. This portion can bemodified by rotating collar 106 using grooves 114.

FIG. 4B shows a perspective view of the adjustment assembly 108. Therelationship between nose piece 1104, lancet stop 102 and collar 106 isillustrated.

FIG. 4C shows a cross-sectional view along the longitudinal axis. Asshown in FIG. 4C, lancet stop protrusions 244(a) and 244(b) interfacewith adjustable collar 106. Thread or cam surface 107 enables axialmovement of the lancet stop 102 within nose piece 1104. Lancet stopdistal surface 222 is spaced from nose piece distal surface 168 suchthat lancet stop orifice 246 is aligned with nose orifice 184. Thispermits a portion of a stylet to emerge a predetermined distance fromnose piece 1104, based on the setting of lancet stop 102. Notch 112permits a user or patient to view the setting on collar 106.

FIG. 4D shows a cross-sectional view along the radial axis. Therelationship of the nose orifice 184, lancet stop 102, collar 106 andgrooves 114 is illustrated.

FIGS. 4E-4H show an embodiment in which the nose portion 104 and tipthread member 116 are distinct elements. (This is similar to theembodiment discussed in relation to FIGS. 3D-3F discussed above.)

FIGS. 4E and 4G show perspective views of nose portion 104, with notch112 and collar 106. FIGS. 4E and 4G also show a covering 115, which istypically a lens for magnifying the setting.

FIGS. 4F and 4H are similar to FIGS. 4C and 4D, respectively, exceptthat the nose piece shown as 1104 in FIGS. 4C and 4D is two pieces;specifically 104 and 116 in FIGS. 4F and 4H. FIG. 4F shows lancet stop102 inserted in nose portion 104 and protrusions 244(a) and 244(b)interfacing with collar 106. Pin protrusion 468 and covering 155 arealso shown.

FIG. 4H shows the relationship between nose orifice 184, lancet stop102, nose portion 104, tip thread member 116 and collar 106.

FIGS. 5A and 5B show a first embodiment of the adjustment assembly 108.FIG. 5A shows the adjustment assembly 108 suitably attaches to the bodyassembly 136 of a lancer device. The adjustment assembly 108 has twoportions. These are an outer member and an inner member. The outermember is shown as nose portion 104 and adjustment member 106. FIG. 5Bshows outer member as element 1106, which is suitably prevented fromtranslation with respect to tip thread member 116.

As shown in FIG. 5A, the outer member 104, 106 has a distal portiontoward orifice 184 and a proximal portion toward body assembly 136.Surface 168(a) is an exterior surface and surface 168(b) is an interiorsurface of outer member 104, 106.

Inner member, also referred to as lancet stop herein, 102 has exteriordistal surface 222(a) and interior distal surface 222(b). Inner member102 also has orifice 246 and protrusions, or posts, 244(a) and (b).These protrusions 244(a) and 244(b) interact with slots 165(a) and165(b), respectively, to prevent inner member 102 from rotating relativeto nose portion 104 when the inner member 102 is being translated bycamming action of adjustment member 106. This translation is back andforth motion, with virtually no rotation of inner member 102. Thus,rotation of adjustment member 106 will cause surface 107 to axially moveinner member 102 and determine the distance between inner member distalexterior surface 222(a) and outer member 104 interior surface 168(b).The outer member 104 does not move axially. A propelled lancet willencounter inner member distal interior surface 222(b). The larger thegap between distal portions of the inner member 102 and the outer member104; the less the penetration depth. Similarly, the closer inner member102 distal exterior surface 222(a) is to outer member 104 interiorsurface 168(b); the greater the penetration depth.

FIG. 5B shows the adjustment mechanism 108 in which the outer member isa single member 1106. Member 474, which is attached to tip thread end116, interfaces with slot 476 of nose member 1106 to prevent translationof the nose member 1106 relative to body assembly (not shown) or tipthread member 116, which is suitably attached to the body assembly, byinteracting with slot 165 when nose piece 1106 is rotated. Nose piece1106 rotational motion causes inner member 102 to move axially bycamming action of surface 107 on protrusion 478. Protrusion 478 of innermember 102 prevents substantial rotation of inner member 102. Theprotrusion 478 “rides” within slot 165, which allows for axial (back andforth) motion while trapping lancet stop 102 from rotational motion. Thesurfaces 168(a), 168(b), 222(a) and 222(b) are also shown.

FIG. 6 shows a second embodiment 1108 of the adjustment mechanism. Thisembodiment also suitably attaches to a lancer device. The inner member102 has protrusions 244(a) and 244(b). Slots 680(a) and 680(b) engageposts 678(a) and 678(b), respectively, on body attachment member 616.Rotation of outer member 104 translates inner member 102 relative tobody attachment member 616 and rotates outer part 104 due tointerlocking of outer member 104 and body attachment member 616 viamember 674 and member 676. These members 674, 676 axially constrainouter member 104 and body attachment member 616; but permit relativerotation between outer member 104 and body attachment member 616. Theouter member 104 does not move axially away from the body assembly (notshown). Protrusions 244(c) interact with surface 107 to move innermember 102 axially (back and forth) and thereby determine the distancebetween inner member 102 distal exterior surface 222(a) and outer member104 interior surface 168(b). This distance, as stated above, determinesthe amount of a stylet that emerges from orifice 246 and orifice 184.

FIGS. 7 and 8 show a third embodiment of the adjustment mechanism.Adjustment mechanism 308 is suitably attached to a lancer device. Member328 is suitably a part of the adjustment mechanism or, alternatively,the distal portion of the body assembly to which the adjustmentmechanism is affixed. In this embodiment, the user pulls the outermember 304 distally and rotates it, moving the outer member 304 from thestopping face 332. (A plurality of stopping faces are designatedgenerally by numeral 332.) Operation of this embodiment involves a userpulling nose 304 to release protrusion 349 from slot one of the slots,shown generally as numeral 331, therefore, allowing relative rotation of304 and 328. While the relative rotation is occurring, no translationbetween surface 322 and surface 368 occurs. While the outer member 304is pulled away from the body assembly 328, the stopping face 332 ismoved distally so that the protrusion 349 is removed from the associatedslot 331 and is able to float above the slots 331 in the adjustment area380. Distally pulling nose portion 304 disengages protrusion 349 fromthe slot 331, permitting rotation. While rotation is occurring,virtually no translation is occurring. Each slot 331 has unique distanceaway from surface 368 to determine the distance a stylet will emerge.

The user can select a slot by rotating the outer member 304 so that anew slot of the plurality of slots, shown generally as element 331, isaligned with the protrusion 349 and a new stopping surface 332(b) isengaged as the spring 327 biases the outer member 304 toward the bodyassembly 328.

When the protrusion 349 is engaged to a particular slot 331, the outermember 304 cannot rotate relative to the body assembly 328. Thus, themotion of the user is a pull, rotate, and return to set the adjustmentassembly 308.

Outer member 304 has interior distal surface 368(a), exterior distalsurface 368(b), and orifice 384. A plurality of slots (showncollectively as element 331, and specifically as 331(b) and (c)) aredisposed on the interior of member 304. Each slot 331 has a distinctaxial depth and interfaces with pin, also referred to as protrusion, 349to establish a relationship between inner member 302 and outer member304; and more particularly, a relationship between inner member distalexterior surface 322(b) and outer member interior surface 368(a).Element 329 provides a surface for biasing spring 327 to act against.Spring 327 can bias outer member 304 to body assembly 328 near theproximal portion of outer member 304. This provides attachment of outermember 304 to the body assembly 328.

Spring member 327 is used to bias the outer member 304 relative to theinner member 302 and enables the adjustment assembly 308 to lock intoposition by biasing pin 349 into a selected slot 331. Element 306 is araised ridge on inner member 302 which anchors biasing spring 327.

FIGS. 9A and 9B show cross-sectional and cut-away views, respectively,of the third embodiment of the adjustment assembly 308. FIGS. 9A and 9Bshow the relationship of body assembly 328, spring 327, outer member304, inner member 302, protrusion 349, and surfaces 322(b) and 368(b).

FIGS. 10A and 10B show perspective and cross-sectional exploded views,respectively, of the fourth embodiment of the adjustment assembly 408.This embodiment utilizes a collar member 335 having interior cammingsurface 333 to attach inner member 302 and outer member 304 to bodyassembly 328.

As shown in FIGS. 10A and 10B, the interior surface of outer member 304has a plurality of slots 331(a) . . . (d) (where d is any numbercompatible with the dimensions of the outer member). Protrusion 349,disposed on an exterior surface of inner member 302, suitably interfaceswith a selected slot 331(a) . . . (d) in a substantially matingrelationship. A user or patient selects a desired penetration depth bypulling and rotating the outer member 304 such that protrusion 349 abutsan interior surface of a slot 331(a) . . . (d). The inner member 302 isheld in position; and surface 322(b) is fixed relative to surface368(a).

Camming surface 341 is disposed in body assembly 328 for attachingassembly 328 to a lancer device. Alternatively, assembly 328 is suitablythe distal portion of a lancer device. Camming surface 341 is alsosuitably utilized to attach a proximal portion of inner member 302 toassembly 328.

Ridge 374 provides a surface that interfaces with spring 327 and biasesouter member 304 towards inner member 302.

Alternatively, another design of this embodiment involves the protrusionmounted on the interior of the nose portion 304 and slots located in theinner member 102. This accomplishes the same purpose as the pull andtwist embodiment described above. The main difference is that thelocation of the protrusions and slots has been reversed.

FIGS. 11A, 11B and 11C show exploded views of a fifth embodiment of theadjustment mechanism 608.

FIGS. 11A-11C show nose portion 304, with a protrusion 312. Also shownis a first annular ring member 350, spring 327, a second annular ringmember 345, inner member 302 and body assembly 328.

The first annular ring member 350 has notches 356, 358 and the annularring member 350 is used to retain spring 327. The second annular ring345 has an extended region 360, one or more notches (shown as numeral354) and surfaces 352. The first annular ring member 350, spring 327 andsecond annular ring member 345 provide a connection to hold the innermember 302 in a fixed relationship relative to outer member 304, suchthat protrusion 349 abuts a selected slot, (slots shown as 331(a) . . .(e) in FIG. 11B, although any suitable number of slots is possible) onthe interior surface of nose portion 304. Protrusion 312 provideslocking for ring 345 into nose 304 by interfacing with notch(es) 354.

FIGS. 12A and 12B show a sixth embodiment of the adjustment assembly708. Body assembly member 328 has interior surface 362 for interfacingwith surface 366 of inner member 302, thereby affixing inner member 302to body assembly 328. Ring member 345 has one or more extended surfaces360 (two surfaces 360(a) and 360(b) are shown, but any suitable numbercould be used). Extended surfaces 360(a) and 360(b) interlock withaperture 364 of outer member 304. Spring 327 abuts ridge 306 and isinserted into ring 345 to bias the inner member 302 towards outer member304. The protrusion 349 on inner member 302 interfaces with a selectedslot 331 (shown in FIG. 12B), to establish a relationship between innermember 302 and outer member 304.

FIG. 13 shows a seventh embodiment of the adjustment assembly 808. Thisembodiment is similar to the sixth embodiment, except that the innermember 302 has a camming surface or, alternatively, screw threads 366,for interfacing and locking with surface 362 of body assembly 328.Similar elements discussed in relation to FIGS. 12A and 12B are notdiscussed in relation to FIG. 13.

FIG. 14 shows an eighth embodiment of the adjustment assembly 908. Thisembodiment is similar to the sixth and seventh embodiments, except thatthe outer member 304 has a camming surface or, alternatively, screwthreads 370, for interfacing and locking with surface 372 of member 345.Similar elements discussed in relation to FIGS. 12A, 12B and 13 are notdiscussed in relation to FIG. 14.

Referring back to FIG. 2, arming mechanism 166 is used to arm or cockthe lancer device 10, prior to firing, by positioning support mechanism175 in a state of increased potential energy. Arming mechanism 166suitably includes inner knob 124, return spring 126 and knob cap 122.The arming mechanism also suitably includes sleeve portion 186, whichwill also be discussed in relation to the ejection mechanism.

Sleeve portion 186 is typically a hollow, substantially cylindricalstructure disposed within body assembly 136 and attaches to bodyassembly 136 by one or more protrusions shown as element 252 located onthe exterior surface of sleeve 186 interfacing with matched detentswithin the body assembly 136. Protrusions 252 are suitably cantileveredbeam members, and any number compatible with the design of sleeve 186could be used.

Inner knob 124 suitably a cylindrical hollow member and has radial ribs134 on the exterior surface for preventing rotation of the knob cap 122during cocking, as well as ensuring minimal movement of knob cap 122when knob cap 122 is extended. Axial ribs 134 of inner knob 124 preventrotation of the inner knob 124. Protrusions 564 on inner knob 124 areused to attach inner knob 124 to knob cap 122. Return spring 126 issuitably disposed within inner knob 124 and is used to retract thesupport mechanism 175 after the lancer device 10 has been fired. This isa safety feature that prevents the stylet from remaining in an extendedposition after being fired. It also increases patient comfort since thestylet will swiftly retract after puncturing the patient's skin. Knobcap 122 suitably affixes to inner knob 124. Inner knob 124 and returnspring 126 are disposed within body section 136. Disposed within theinner knob 124 is proximal portion of support mechanism 175.

Support mechanism 175 suitably includes a support structure (alsoreferred to as a support member, guide member or plunger herein) 146,triggering means 132, and spring retainer 128. At the distal end ofplunger 146 a lancet, having a stylet, is suitably mounted. The plunger(guide member) 146 has splines 169, tangs 176, 276 (typically there areany suitable number of tangs, but only two will be described in detailherein), dampening wisp 154, disk members 449(a) and 449(c) (other diskmembers are discussed herein) and detents 144(a) and 144(b).

Plunger 146 is typically an elongated member fabricated from a polymermaterial, enabling it to be relatively rigid at the distal portion,where it interfaces with a lancet, suitably by having a receptacle(receptacle not shown in FIG. 2) with dimensions sized to hold aproximal portion of a lancet in a mating relationship. Splines 169enhance a linear pull motion to arm the device 10.

Tangs 176, 276 are protrusions extending outwardly from the plunger 146.(There may be more or less than two tangs on plunger 146, but only twoare depicted in FIG. 2.) The tangs 176, 276 are suitably wedge-shaped toengage yoke latch 139 and hold plunger 146 in a fixed position afterdevice 10 is armed and prior to its firing.

Triggering means 132 is suitably a coil spring that is capable of beingcompressed and is disposed around splines 169, although any suitablematerial could be used to perform the function. Triggering means 132 iscompressed when the knob cap 122 is retracted. In a compressed state,the triggering means 132 has higher potential energy.

Dampening mechanism is suitably one or more protrusions or wisps 154(although there could be virtually any number of wisps that wouldcomport with the design, only a single wisp will be described herein),which is, for example, a radially outward biased cantilevered beamlocated on plunger 146. When the plunger 146 is actuated, the wisp 154contacts the inner diameter of sleeve portion 186 or body section 136,if sleeve portion 186 is omitted, to provide a frictional force and thusa dampening feature to the plunger 146. This dampening mechanism reducesvibration felt by the patient during plunger movement, which istypically during and shortly after stylet penetration.

Upon assembly, detents 144(a) and 144(b) are pushed through a slit 212in spring retainer 128 and expand so as to maintain plunger 146 andreturn spring 126 in a desired position to allow for arming and plungerretraction. In a preferred embodiment, plunger 146 and spring retainer128 would be a single piece.

Triggering mechanism 172 is used to fire the lancer device 10 such thata desired portion of a stylet is projected through nose orifice 184.Triggering mechanism 172 comprises, yoke latch 139, biasing means 142,and button 138.

Yoke latch 139 is suitably a U-shaped or C-shaped rigid member althoughvirtually any suitable shape would be acceptable for forming asubstantially interference fit with tangs 176, 276 on plunger 146 anddisposed in body assembly 136. Yoke latch 139 has windows (not shown inFIG. 2) for interfacing with tangs 176, 276 so as to control theposition of tangs 176, 276. When the lancer device 10 is in the loadedposition, the yoke latch 139 engages tangs 176, 276 such that plunger146 remains in a state of higher potential energy (i.e., triggeringspring 132 is compressed).

Biasing means 142 is disposed between plunger 146 and yoke latch 139,and biases, radially outward, the latch 139. When actuated the biasmeans 142 is overcome, releasing yoke latch 139 thereby permitting tangs176, 276 to pass through yoke latch 139 and plunger 146 pushes a lancetin the distal direction toward nose portion 104. The biasing means 142is suitably a leaf spring, coil spring, compressible elastomericmaterial such as a foam rubber cube, cantilevered beam, torsion springor plastic member. The biasing means as shown as leaf spring 142 in FIG.2, which is actuated by button 138. Button 138 includes cantileveredportion 192 and cavity 194.

The release member, or button, 138 has a bottom surface 262 thatcontacts yoke latch 139 to overcome bias means, which is shown as a leafspring, 142. Protrusion 238 retains the button 138 in the body assembly136. Button 138 is typically mounted through button orifice 216 of bodyassembly 136. This design allows linear travel of the plunger 146because the plunger 146 is not biased in any direction due to triggeractivation. The straighter plunger path reduces vibration and radialmotion and thus reduces pain felt by the patient.

FIGS. 15A and 15B show an isometric exploded view 30 of the yoke latch139 and plunger member 146. The plunger member 146 has a receptacle 254sized to interface with a lancet in a substantially mating relationship.FIG. 15A shows a view without a sleeve and FIG. 15B shows a view withsleeve 186. As shown in FIGS. 15A and 15B, the yoke latch 139 hasproximal face 218 and distal face 220, and mounts over the biasing means142. The yoke latch 139 has yoke latch windows (also referred to asnotches herein) 152, 153 and yoke latch distal face ramps 182, 183 (ramp183 shown in FIG. 15A and ramp 182 shown in FIG. 15B). These sections ofyoke latch 139 facilitate movement by plunger 146.

FIG. 15A shows tangs 176 and 276 disposed on opposing sides of plunger146. It should be apparent to those skilled in the art that the quantityand location of the tangs, which are substantially wedged-shapedprotrusions, is a design choice. Tang 176 has a distal face 178perpendicular to the line of action, which acts to rest on yoke latchproximal face 218 when the plunger member 146 is retracted into the“armed” position. The tang 176 is angled to form a ramp 180 that can acton a corresponding ramp 183 of the distal face 220 to the proximal face218 of the yoke latch 139. Tang face 178 engages proximal face 218 ofyoke latch 139 when in an armed state. By pulling the plunger 146 in theproximal direction such that the plunger tang ramp 180 engages the yokelatch distal face 220, the yoke latch 139 is moved in a downwarddirection by the ramp 180 surface. As the yoke latch 139 lowers, thetangs 176, 276 move through yoke latch windows (or notches) 152, 153.Once the tangs 176, 276 are through windows 152, 153, the yoke latch 139snaps upward into a fixed position due to pressure exerted by biasingmeans 142. This fixed position of yoke latch 139 prevents movement ofthe plunger 146.

The plunger 146 suitably has a non-circular cross-section as shown inFIG. 15A. The plunger 146 is relatively rigid and resists columnardeformation thereby providing support and guidance for a lancet as thelancet is propelled.

In order to arm the device, the knob cap (shown as element 122 in FIG.2) is retracted. Tangs 176, 276 on plunger 146, which typically have awedge shape, displace latch 139 radially inward against the bias of thebiasing means shown as 142. In doing so, they are allowed to passthrough the window 152 and while passing through the window, force thelatch 139 into a fixed position. However, since a proximal force isbeing applied to the plunger 146 against the bias of the triggeringspring (shown as element 132 in FIG. 2), the motion continues proximallyas the tangs 176, 276 pass entirely through the yoke latch 139. Once thetangs 176, 276 are positioned on the proximal side of the latch, thebias of the leaf spring 142 forces the yoke latch 139 radially outwardto the “armed position”. Tangs 176, 276 continue slightly passed theyoke 139 and are stopped due to the position of the plunger 146. Theplunger 146 is released and then, due to bias of trigger spring, movesdistally to the recover distance and rest in a fixed position againstthe proximal face 218 of yoke latch 139.

In order to fire the device, the release member (shown as button 138 inFIG. 2) is pressed, which biases the yoke latch 139 against the biasmeans, shown as leaf spring 142 and subsequently the tangs 176, 276 onthe plunger 146 are allowed to pass through the windows 152, 153 on theyoke latch 139. Since the plunger 146 is biased by triggering spring(shown as element 132 in FIG. 2), this occurs rapidly. This designallows linear travel of the plunger 146 because the plunger 146 is notbiased in any direction due to trigger activation. The straighterplunger path reduces vibration and radial motion.

After the axial travel of the tangs 176, 276 passed through the windows152, 153; yoke latch 139 returns to its rest position.

The plunger 146 also has one or more protrusions 449 (these protrusionsare shown in FIG. 15A as 449(a) and 449(c); but are described herein asdisk-like members 449(a) . . . (d), although any suitable number ofprotrusions could be used), that form one or more annular rings aroundplunger 146. This ring is typically non-circular, thereby engaging theinner diameter of the device. These members 449, which are suitably usedin conjunction with wisps 154(a) and 154(b) and/or tangs 176, 276,provide a centering function for the plunger 146 when the plunger 146 ispropelling a lancet.

FIG. 15B shows an exploded view of the latch 139, plunger 146 and sleeveportion 186. FIG. 15B also shows threaded portion 109 of sleeve portion186 and grooved region 190 of sleeve 186. Threaded portion 109 issuitably connected to adjustment collar or the tip thread member toconnect the adjustment mechanism to the sleeve 186. The leaf spring 142is engaged by the sleeve 186 to exert pressure on yoke latch 139.Slotted region 454 of sleeve 186 permits access of plunger 146 to yokelatch 139. Elements discussed in relation to FIG. 15A are not discussedin relation to FIG. 15B.

FIGS. 16A and 16B show a perspective view of yoke latch 139. As shown inFIG. 16A, the yoke latch 139 typically has a substantially U-shape orC-shape design such that the support member passes through interiorsurface 264 through notches 152 and 153 of yoke latch 139. However, theyoke latch 139 suitably can be a member containing a notch for engaginga tang as shown in FIG. 16B.

As shown in FIG. 16A, the yoke latch 139 has windows 152, 153 and rampsurfaces 182, 183. The windows 152, 153 enable the plunger member toslide through the yoke latch 139 to the proximal side 218, and to beheld in a fixed relationship until actuated by pressure applied to anarea 138(a), which overcomes the biasing means (not shown in FIG. 16).Yoke latch 139 also has clamping portions 224, 226 disposed at the openend, for securely holding the yoke latch in position relative to sleevevia a slotted area in the sleeve. (Slotted area in sleeve is shown aselement 454 in FIG. 15B.)

FIG. 16B shows yoke latch 139(b), which is a modified version of yokelatch 139 shown in FIG. 16A. Yoke latch 139(b) does not have a U-shapedor C-shaped design; but instead, performs the latching function with asingle notch 152, a single ramp surface 183, and a single clampingmechanism 226. The area to apply pressure 138(a) is also approximatelyhalf the similar area of FIG. 16A.

FIG. 17 shows the button 138 having cantilevered portion 192 and cavity194. The cantilevered portion 192 facilitates a substantially matingrelationship with the body assembly. The cavity 194 suitably interlockswith the body assembly. Button tang 238 (typically button 138 will havetwo tangs, but only one is shown in FIG. 17) is suitably a cantileveredmember that forms a substantially interference fit with the bodyassembly when inserted into the button orifice (body assembly and buttonorifice shown in FIG. 2). The button tang 238 prevents button 138 fromdetaching from the body assembly. The button 138 has a surface 262 inproximity to the yoke latch. As is obvious to those skilled in the art,the button could be formed on the yoke latch. The button is an optionalfeature and a user could activate the device by pressing directly on aportion of the yoke latch (shown as 138(a) in FIG. 16). A portion 262 ofbutton 138 abuts the yoke latch to overcome the biasing means when thebutton 138 is pushed with the necessary force.

FIG. 18 shows spring retainer 128. Retainer 128 has an orifice 212 forproviding a substantially smooth fit with the plunger member (plungernot shown in FIG. 18). The orifice 212 has an interior surfacecorresponding to the outer diameter of the plunger. The retainer 128 hasa non-circular interior surface for creating a substantially matingrelationship with plunger member as shown herein. The interior surfaceof retainer 128 is suitably any configuration to interact with theplunger. Surface 208 is a proximal surface having one or more orifices210 (a)-(d).

The retainer 128 also suitably has inclined surfaces 213(a) . . . (d)for interfacing with the proximal portion of a plunger, typically thedetents of the plunger hook into the inclined surfaces 213(a) . . . (d).These surfaces facilitate the retainer 128 maintaining the plungerrelative to the retainer 128 and allowing the retainer 128 to retractthe plunger when the retainer 128 is retracted. The retainer 128 alsoretracts the plunger when the retainer 128 is retracted by the returnspring. (Although only four inclined surfaces are shown, typically anynumber compatible with the design of retainer 128 could be used.)

FIG. 19 shows a cut-away view of the lancer device 10 in the pre-armed,or resting, stage. As shown in FIG. 19, lancet 188 has a sharpenedstylet portion 203 that is within device 10 and poised to emerge fromorifice 184 when the device 10 is fired or actuated. In the pre-armedposition, triggering spring 132 is in an open position (i.e., a state ofrelatively low potential energy) because it is substantiallynon-compressed. Return spring 126 is also not fully compressed. Tangs176, 276 are positioned on the distal side of yoke latch 139. Inner knob124 is in a non-extended position. The biasing means (not shown in FIG.19) is biasing yoke latch 139.

Distal surface 168, adjustment mechanism 108, and collar 106 have beendiscussed previously and will not be discussed further here.

FIG. 20 shows a cross-sectional view, taken along the longitudinal axisof the lancer device 10 in the armed position. Similar elementspreviously described will not be discussed in relation to FIG. 20.Similar to the view shown in FIG. 19, the lancet 188 with sharpened endportion 203 is disposed such that the stylet 203 does not emerge fromorifice 184. Trigger spring 132 has been compressed, i.e., in a state ofincreased potential energy by retraction of end knob 122 in the proximaldirection. Tang 176 is positioned on the proximal side of latch 139.Knob cap 122 is not extended.

FIG. 21 shows a cut-away view of the lancer device 10 in the armedposition with knob cap 122 extended so as to expose a section of innerknob 124. In this position tang 176 is on the proximal side of yokelatch 139. The triggering spring 132 is compressed because plunger 146has been retracted by knob cap 122.

In the armed position, the knob cap 122 returns to proximal end of bodyassembly 136, due to the bias of the return spring 126 (e.g., coilspring).

In order to actuate the lancer device 10, the latch 139 must be pushedwith the necessary force to overcome or compress the biasing means andmove the yoke latch 139 to a fixed position.

When button 138 is deliberately pressed with the requisite amount ofpressure, the biasing means, such as a leaf spring is overcome,permitting the yoke latch 139 to move and tang 176 to pass through yokelatch 139, causing plunger 146 to push lancet 188 in the distaldirection. The stylet 203 extends from the nose orifice 184. After thestylet 203 emerges from the nose orifice 184, lancet 188 impacts lancetstop 102, and return spring 126 pulls the stylet 203 back into thelancer device 10.

The lancer 188 has a stylet 203 that is suitably manufactured fromstainless steel.

Nose portion 104, collar 106 and splines 169 have been discussedpreviously in relation to other figures and are not discussed furtherhere.

FIG. 22 shows an exploded view of an embodiment of device 10 that has anejection feature. An ejection mechanism is used to eject a used lancet188 from lancer device 10. The ejection mechanism comprises an ejectionmember in (also referred to as an ejection blade herein) 159, sleeve 186(shown in FIG. 2 previously), and ejection spring 174. The ejectionmechanism operates in conjunction with other components of the device10.

Ejection member or blade 159 (the terms “ejection member” and “ejectionblade” are used interchangeably herein) is suitably a rigid elongatedmember, fabricated from a polymer material, having distal portion 234and proximal portion 236. Ejection blade 159 is mounted in the proximalportion of body assembly 136, suitably to retaining plug 128 such thatthe blade 159 is affixed to the inner diameter of body assembly 136.Typically, the blade 159 would be integral to the body assembly 136.Ejection member 159 has a distal portion 234 for interfacing with thelancet 188. A portion of ejection blade 159 may also be disposed insleeve 186, which is disposed in body section 136, or alternatively, theejection blade 159 may be disposed in body section 136, without sleeve186.

Sleeve 186 is used to provide support for the ejection blade 159 and toprovide a connection between the body section 136 and nose cap. Thesleeve 186 has a one or more protrusions, or camming features shown as252(a) and 252(b), which is suitably two cantilevered beams that aredisplaced when the end knob 122 is retracted while the nose portion isdetached from body assembly 136.

The proximal end of sleeve 186 permits the plunger 146 to move axiallywithin sleeve 186. As shown, the sleeve 186 has an interior surfaceconfiguration that forms a substantially interference fit, such that theclearance between the plunger 146 and the inner diameter of the sleeve186 is minimized. Although the configuration is non circular, virtuallyany configuration would be acceptable.

Ejection spring 174 is suitably a coil spring capable of beingcompressed that is disposed between proximal portion 236 of blade 159and the distal portion 236. Sleeve 186 is typically fixed to the bodyassembly 136; but is also capable of restricted axial movement. Ejectionspring 174 is used to bias sleeve 186 in the distal direction. As theplunger 146 is moved proximally, the sleeve 186 moves proximally againstbias of the ejection spring 174. The distal portion of the blade 234contacts lancet 188 and prevents it from retracting in body assembly136, and thus, lancet 188 becomes detached from plunger receptacle 254.The detached lancet 188 is not retained and will suitably exit throughbody orifice 214.

In operation, the ejection mechanism enables a used lancet to be removedfrom the device without a user or patient touching it.

The ejection feature will now be described. After a stylet has beenfired, by releasing latch 139, and is retracted into the body assembly136 by return spring 126, the nose cap and/or the entire adjustmentmechanism is removed. Knob cap 122 can be retracted further when thenose cap is detached because the nose cap is not exerting a force onbody assembly 136 because it is no longer connected to sleeve 186.

A user or patient pulls on the end knob 122 in a similar fashion as thearming force to a first position, however, with the nose cap removed theknob cap 122 can be retracted further in the proximal direction thanduring the arming process. The return spring 126 is compressed first.Upon further retraction of knob cap 122 to a second position, which isfurther in the proximal direction than the first position, retainer 128and plunger 146 are retracted, compressing triggering means shown astriggering spring 132. Next, sleeve 186 is retracted axially, in theproximal direction, compressing ejection spring 174. Ejection spring 174is biased to maintain the sleeve 186 in a distally forward position. Themovement of plunger 146 and sleeve 186 in the proximal direction causeslancet 188 to come into contact with ejection blade 159. Lancet 188contact with the ejection blade 159 prevents the lancet 188 fromretracting further and thus, lancet 188 is detached from plunger 146. Auser can point the distal portion of the body assembly 136 into anappropriate refuse container and the lancet 188 will fall out of thelancer device 10 through body orifice 214.

Thus, the ejection mechanism permits disposal of a used lancet 188without a user touching it, and without an additional control member.

In an alternate embodiment, the sleeve 186 has a protrusion 477 mountedon the inner diameter that serves to prevent the lancet 188 fromretracting and thereby detaching the lancet 188 from the plunger 146.

Button 138, inner knob 124 and button orifice 216 have been discussedpreviously.

FIGS. 23 and 24 show a cut-away view of the lancer device 10, withejecting mechanism. The embodiment shown in FIGS. 23 and 24 shows a wirelatch 139(a) that serves the function of the yoke latch describedpreviously. The wire latch 139(a) is suitably an annular oval-shapedring, which is used to retain the plunger 146. When the tang 176 of theplunger 146 passes to the proximal side of wire latch 139(a), (forexample, during retraction of the plunger 146) the wire latch 139(a)interfaces with the tang 176 to maintain the plunger 146 in an armedposition. A force sufficient to displace the wire latch 139(a) permitsthe tang 176 to pass through the wire latch 139(a) and the plunger 146to be propelled in the distal direction.

The device 10 can be discussed in terms of various states of operation.These include: pre-armed, cocked, armed, activated, and ejecting.

In the pre-armed, or natural, state the triggering spring 132, ejectionspring 174, and return spring 126 are substantially non-compressed.

In the cocked state, the triggering spring 132 and the return spring 126are substantially compressed; but the ejection spring 174 issubstantially non-compressed. The end knob 122 is extended proximally.

In the armed state, the triggering spring 132 is substantiallycompressed, the return spring 126 and ejection spring 174 aresubstantially non-compressed. The end knob 122 is abutting the bodyassembly 136.

In the activated state, the return spring 124 is substantiallycompressed; but the neither the triggering spring 132 nor the ejectionspring 174 is compressed.

In the ejection state, the triggering spring 132, return spring 124, andejection spring 174 are substantially compressed. The end knob 122 isretracted to a second position, which is proximal to the extendedposition of the cocked state. This second position is achieved becausethe nose cap has been detached; enabling further retraction of the endknob 122 than when the nose cap is attached to the body section 136.

As shown in FIG. 23, the device 10 is in the activated state. Triggeringspring 132 and ejection spring 174 are not fully compressed. As shown inFIG. 24, the device is in the armed state, in which triggering spring132 is compressed and ejection spring 174 is slightly compressedproviding a bias in the distal direction. The return spring 126 is notcompressed. Elements discussed previously are not discussed in relationto FIGS. 23 and 24.

FIG. 25 shows a cross-sectional view of lancer device 10, in theejection state, ejecting a lancet 188. Triggering spring 132, returnspring 126 and ejection spring 174 are compressed. Blade 159 preventslancet 188 from retracting as plunger 146 is retracted by applying aforce in the proximal direction via knob cap 122, which retracts innerknob 124.

Detents 144(a) and 144(b) and body assembly 136 have been discussedpreviously.

FIG. 26 shows a perspective view of sleeve 186. As shown in FIG. 26,sleeve 186 has threaded portion 109, for connection to tip thread member(not shown). Portion 252(a) is a member that suitably extends radiallyoutward from the sleeve 186 and is used to hold sleeve 186 in acontrolled position within the body assembly. (When the sleeve 186 isused in conjunction with the ejection mechanism, described herein, thesleeve has controlled axial motion. When the sleeve is used without theejection mechanism, it is in a fixed position.) In FIG. 26, proximalportion of sleeve 186 has an orifice 373 similar to the orifice in theretaining plug 128 and thus, the plunger can move axially within sleeve186. The dimensions of the orifice 373 are sized to result in minimalradial movement of the plunger within the sleeve 186. This facilitatescontrol and improves the trajectory path of the plunger, therebyreducing undesired radial motion. Detents 190 enable secure positioningof sleeve 186 in the body portion. Slotted area 454 provides access ofthe latch to tangs of the plunger since the plunger is disposed withinthe sleeve 186.

FIGS. 27 and 28 show the vibration dampening mechanism of the device.FIG. 27 shows a perspective view of plunger 146 with wisps 154(a) and(b). Wisps 154(a) and (b) (typically there are any number of wisps butonly two are described herein) are suitably cantilevered protrusionsextending from plunger member 146. Alternatively, the wisps 154 may bemounted directly on proximal tangs, which are similar to tang 176 exceptthat they are located proximal to the tang 176 on plunger 146. Theproximal tangs are illustrated as tang 456(a).

The vibration dampening mechanism provides stabilization during armingof the device, actuation of the device and when the lancet isretracting, after being fired.

Also, disk surfaces 449(a) . . . (d) are disposed on plunger 146. Thesesurfaces provide a centering feature for the plunger 146. Alternatively,these surfaces could be a peg-like protrusion to interface with acorresponding rail or channel in either the inner diameter of the bodyassembly or the sleeve.

A protrusion 458 is formed proximal to surfaces 449(a) and 449(b), andis suitably a raised member for limiting the travel of the plunger 146in the proximal direction. The raised member 458 acts as a positive stopwhen the plunger 146 is being retracted in the proximal directionbecause it interfaces with the sleeve or body to prevent furtherretraction of the plunger 146. When the device is in the ejection state,the raised member 458 facilitates movement of the sleeve proximally.

FIG. 28 shows a detailed view of wisps 154(a) and 154(b). The wisps154(a) and 154(b) are suitably fabricated from the same material as theplunger 146 and are mounted so as to have the capability to expandslightly and thereby interact with the inner diameter of a structure inwhich the plunger 146 is disposed i.e., sleeve or body assembly. Thisinteraction decreases the vibration of the plunger 146 when actuated andwhen retracting. Tangs 176 and 276 are also illustrated.

FIG. 29 shows a centering feature of the instant invention. AlthoughFIG. 29 shows a cross-sectional view of the body assembly 136 withsleeve member 186, this feature is suitably used with or without asleeve member 186. The inner diameter has one or more surfaces 562(a) .. . (d) that are designed to interact with a portion of plunger member146. Although FIG. 29 shows four raised surfaces 562(a) . . . (d), therecould be any number that comports with the design of the structure.

The surfaces 562(a) . . . (d) provide specific contact points betweenthe plunger 146 and an inner diameter of the sleeve 186 or body 136.These surfaces 562(a) . . . (d) are suitably one or more channels, oneor more pegs, or one or more rails.

The plunger 146 member suitably has one or more protrusions 449(a) . . .(d); such as disks, wisps, cantilevered beams, or pegs that interactwith the inner diameter surfaces 562(a) . . . (d) of the body assemblyor sleeve member. This interaction serves to center the plunger 146 asit is propelled. The plunger 146 typically has an outer diameter ofapproximately 0.333 inch and the specific surface of body 136 or sleevepermits a minimal clearance, preferably less than 0.008 inch for theplunger within the body or sleeve. This provides for a substantiallysmooth fit between the plunger 146 and inner diameter of body assembly136 or sleeve 186 permitting the plunger 146 to move primarily onlyaxially within the body 136 or sleeve 186. Tangs 176 and 276 are alsoshown.

The lancer has been described above, a method of using the apparatuswith all the mechanisms working in concert will now be describedreferring to the components identified in FIGS. 1-29.

The nose portion 104, with lancet stop 102, and collar 106 are detachedfrom the sleeve 186 or body assembly 136. An unused lancet 188 isinserted into a receptacle 254 of plunger 146. The nose portion 104 andcollar 106 are attached to body section 136. The collar 106 is turned toa desired setting for drawing sufficient blood. This setting istypically chosen from numbers 1-6. The device 10 is armed by pullingback on knob cap 122, which locks plunger 146 in a high potential energystate because return spring 126 and triggering spring 132 aresubstantially compressed. The knob cap 122 is then released and returnedto its starting position and the return spring 126 is substantiallynon-compressed.

The pressure surface 168(b) is pressed against a desired area of thepatient and the device is actuated by pressing button 138 with thenecessary force to compress biasing means 142. Biasing means 142, onceovercome, moves latch 139 so tangs 176, 276 pass through latch 139 inthe distal direction. The lancet 188 carried by plunger 146 isaccelerated into the lancet stop 102 by the force of the triggeringspring 132. The stylet 203 emerges from nose orifice 184 with sufficientenergy to pierce the skin of a patient and the lancet 188 is stopped bythe lancet stop 102. Return spring 126 retracts stylet 203 into device10 via lancet 188. After obtaining the desired quantity of blood, thenose portion 104 is detached from body section 136. The knob cap 122 isthen retracted in the same fashion as arming to a first position. Thereturn spring 126 is compressed. Further retraction compressestriggering spring 132 and yet further retraction compresses ejectionspring 174, all the while applying a force to the plunger 146, causingplunger 146 to be retracted. At this point, ejection blade 159 contactslancet 188 to prevent the lancet 188 from retracting with the plunger146, causing release of the lancet 188 from the plunger 146.

FIGS. 30-33 show an alternate embodiment of the lancer device that hasan oblong shape. FIG. 30 shows an exploded view of a lancer 20. Lancer20 has an oblong outer body section 536 connected to an end knob 522.End knob 522 is used for arming or cocking the device 20 and is sized tobe compatible with the oblong shaped body 536. Body section 536 suitablyhas an orifice 516 in which a release means, such as a trigger or button538, is mounted. Disposed within body 536 is a plunger or shaft 546. Atip assembly 508 suitably includes an inner member 502, outer adjustmentmember 504, and nose portion 506. In this embodiment tip assembly 508can be detached from the body assembly 536. Adjustment member 504 isconstrained from linear motion in nose portion 506. Adjustment member504 only moves radially. The inner member, also referred to as a lancetstop, 502 has a full thread-form, mating into the adjustment member 504.The user rotates radially the adjustment member 504 to change therelative distance between the adjustment member 504 and the lancet stop502. The slots 509(a) and 509(b) interact with posts (posts shown as 593(a) and 593(b) in FIG. 33) to prevent radial motion of stop 502 andpermit the stop 502 to move only axially due to the camming motion ofthe thread forms. This has been discussed herein in relation to FIG. 6.

The oblong-shaped embodiment 20 uses posts to eliminate relativerotation between the stop 502 and nose portion 506.

When armed, the yoke latch 539 retains one or more tangs (shown as asingle tang 576) of plunger 546 in yoke latch window 553. Yoke latch 539is mounted to sleeve 586. Mounting points 598(a) and 598(b) on yokelatch 539, which are for example, apertures in yoke latch 539, attach toposts 504(a) and 504(b) of sleeve 586, respectively. These mountingpoints 598(a) and 598(b) form a pivot axis when yoke latch 539 isactuated. Actuation is achieved by overcoming biasing means 542 torelease yoke latch 539. The yoke latch 539 is pivoted about the pivotaxis against biasing means 542, which is suitably a spring. This causesthe yoke latch 539 to move perpendicular to the axis of the device 20,enabling tang 576 on plunger 546 to pass through window 553 of yokelatch 539. After actuation, proximal fingers 579(a) and 579(b) (referredto as 579 herein) on the yoke latch 539 abut distal fingers 581(a) and581(b) (referred to as 581 herein) of the inner knob 524, therebypreventing engagement of the yoke latch 539 on tang 576 of the plunger546. The device can be armed by retracting end knob 522 in the proximaldirection since this will cause the distal fingers 581 of inner knob 524to disengage the yoke latch proximal fingers 579 and yoke latch 539 canengage tang 576 on plunger 546. This is accomplished by the yoke latch539 pivoting about the pivot axis to a position in which the yoke latch539 can engage the tang 576. Triggering spring 523 and return spring 526perform triggering and return functions, respectively, as discussedherein. Retainer 528 facilitates retraction of the plunger 546. Members505(a) and 505(b) provide support for the posts. Member 525 providesalignment for fingers 581(a) and 581(b).

FIGS. 31A and 31B show the device 20 after firing. (FIG. 31B is apartial cut-away view of the device 20.) Proximal finger 579(a) on yokelatch abut distal finger 581(a) of inner knob. This interface preventsthe plunger from being retracted into a loaded position from pressureexerted at the distal portion of device 20. This reduces the possibilityof inadvertent arming or loading of device 20 and aids in insertion andremoval of a lancet. Body assembly 536, end knob 522, button orifice516, button 538, adjustment member 504 and nose 506 have been discussedpreviously.

FIG. 32 shows a cut-away view of the assembled device 20. Therelationship of body assembly 536, lancet stop 502, adjustment member504, nose portion 506 and end knob 522 is shown. The elements discussedpreviously are not discussed further here.

FIG. 33 shows an cut-away view of tip assembly 508 with post 593(a),which prevents rotation of lancet stop 502. Adjustment member 504 hasdetents 583(a) and 583(b) to prevent axial movement of adjustment member504. Support member 505(a) is also shown.

FIG. 34 shows the latch 539 and plunger 546 as used in the devicedescribed as device 20 above. The latch 539 has mounting point 598(a),which enables the latch to move perpendicular to the axis of motion ofthe plunger 546. When latch 539 is actuated, plunger tang 576 passesthrough window 553, enabling the plunger 546 to move distally. Fingers579(a) and 579(b) are used to abut proximal fingers (not shown) andthereby prevent retraction of the plunger 546 when the latch 539 hasbeen actuated. When the plunger is retracted from the proximal end(i.e., end knob, shown as element 522 previously), the distal fingers579(a) and 579(b) disengage the proximal fingers. This is a safetyfeature that will help prevent inadvertent loading of a lancet in thedevice.

FIGS. 35A-35C show a stylet 203 having an outer diameter of 31 gauge orsmaller (i.e., higher gauge number). As the blood volume requirementsfor meters become smaller and smaller, less blood is required from theextraction site. Smaller gauge stylets will achieve smaller volumesbecause of the smaller diameter. The smaller diameter should requirereduced penetration force and reduced patient trauma, which results inincreased patient comfort. The stylet with a gauge of 31 or higher(i.e., smaller outer diameter) specifically targets a blood volume of2.5 micro-liters for testing.

A 31 gauge stylet 203 is suitably fabricated from stainless steel andhas an outer diameter of approximately 1×10⁻² inch, +/−4×10⁻⁴ inch. Theprimary angle, shown as angle 209 in FIG. 35A, is suitably betweenapproximately 7 and 11 degrees, and preferably about 9 degrees. Theprimary angle 209 forms a surface 210. The secondary angle, shown as 211is suitably between approximately 14 and 18 degrees, and preferablyabout 16 degrees, and forms surface 212. The secondary angle is acompound angle formed by rotating the stylet about the axis of thedevice by the amount of the primary angle. For example, in thisembodiment, the stylet 203 was rotated 9 degrees, and a 16 degree anglewas used as the secondary angle to form the surface 212.

A 32 gauge stylet (with similar geometry as described in relation to the31 gauge stylet) has an outer diameter of approximately 9×10⁻³ inch,+/−4×10⁻⁴ inch.

A 33 gauge stylet has an outer diameter of approximately 8×10⁻³ inch,+/−4×10⁻⁴ inch.

The 32 and 33 gauge stylets are suitably fabricated with similar primaryand secondary angles as those described in relation to the 31 gaugestylet.

FIG. 36 shows the geometry of a 31 gauge stylet 203 with sharpenedsurface 212. This geometry also applies to lancets having a smallergauge. The geometries of these stylets require lower penetration forces.

FIG. 37 shows a stylet 203, with an outer diameter of 31 gauge orsmaller, mounted to a lancet 188. A shield member 207 is suitably usedto cover the stylet 203 by interfacing with portion 189 of lancet 188.The length of stylet 203 is typically between approximately 0.115 inchand 0.163 inch.

The stylet 203 also suitably has a rotation angle between approximately17 degrees and 35 degrees. The stylet 203 is also suitably lubricated toimprove blood flow from a puncture wound made by the stylet.

Other variations and modifications of this invention will be obvious tothose skilled in this art. This invention is not to be limited except asset forth in the following claims.

1.-5. (canceled)
 6. An apparatus, comprising: a body assembly, having aproximal portion, a distal portion, and an orifice disposed at thedistal portion; a knob cap engaging the proximal portion of the bodyassembly; a guide member having a distal end and a proximal end, whereina receptacle is located at the distal end of the guide member and theproximal end of the guide member is engaged with the knob cap, whereinthe proximal end of the guide member is capable of being retracted to afirst armed position or to a second position, which is further in aproximal direction from the first armed position, by pulling the knobcap in the proximal direction, the guide member being disposed in thebody assembly for guiding a lancet received in the receptacle; and anejection blade, fixedly disposed in the body assembly, and contactingthe lancet to prevent retraction of the lancet relative to the bodyassembly when the proximal end of the guide member is being retracted tothe second position, thereby ejecting the lancet from the receptacle atthe distal end of the guide member through the orifice disposed at thedistal portion of the body assembly.
 7. An apparatus according to claim6, wherein the knob cap slidably engages the proximal portion of thebody assembly.
 8. An apparatus according to claim 6, wherein theproximal end of the guide member comprises at least one detent whichengages the knob cap.